1973 Porsche Carrera RS/RSR 2.9 Lightweight

Porsche took over in sports car racing where Ferrari left off in the early 1970s. After winning the World Sports Car Championship in 1970, 1971 and 1972, Porsche reacted to the FIA decision to swing from sports-prototypes to more production-based machinery by selecting their eight-year-old street-going 911 to be further developed as a racing car. For the car to be homologated, they needed to deliver a batch of 500 cars-something the sales and manufacturing people thought might be impossible.

For several years, starting with the 911R of 1967, Porsche had built and sold highly limited runs of 911s modified for either race or rally use. But making and selling 500 looked to be a formidable task. However, the cars sold so fast Porsche decided to add two additional runs of 500 plus some extra cars bringing total production to 1,580.

Production was achieved by "converting" stock 2.4 911S cars into Carrera RSs. Body changes included thinner steel for...